1. Field of the Invention
The present invention relates to an apparatus for supporting an electric-component mounter and particularly to the art of reducing the vibration of a floor which supports the electric-component mounter.
2. Related Art Statement
There is known an electric-component (xe2x80x9cECxe2x80x9d) mounter which includes a circuit-substrate (xe2x80x9cCSxe2x80x9d) supporting device, an EC supplying device, and an EC mounting device. Those devices are supported on a common base member which is provided on the surface of a floor. The EC mounting device receives, from the EC supplying device, ECs (e.g., electronic components) as elements of an electric circuit (e.g., an electronic circuit), and mounts the ECs on a CS (e.g., a printed circuit board) supported by the CS supporting device. In this sort of EC mounter, at least one of the EC mounting device, the CS supporting device, and the EC supplying device includes a movable member which is movable for transferring the ECs supplied from the EC supplying device or mounting the ECs on the CS. Therefore, when the ECs are mounted on the CS, the movable member is a plan view of accelerated and decelerated and accordingly the base member is subjected to vibration. Since the base member is fixedly supported by the floor, almost all the vibrational energy is transmitted to the floor. Thus, not only the base member but also the floor are vibrated. The base member may be fixedly supported by the floor, in such a manner that the floor surface is covered with a leveling sheet formed of steel and the base member is placed on the leveling sheet via a plurality of leveling bolts. In this manner, the level at which the CS is conveyed, and the level at which the EC mounting device and the EC supplying device are provided, can be adjusted. In addition, the plurality of leveling bolts can be contacted with the floor surface at a substantially uniform pressure. Thus, the base member and the floor are connected to each other as if it were a unit. Thus, almost all the vibrational energy is transmitted to the floor.
If a rubber sheet is inserted between the leveling sheet and the floor, the vibrational energy which is transmitted to the floor can be more or less reduced by the elastic deformation of the rubber sheet. However, this reduction is not satisfactory. In a particular case, the frequency of the vibration exerted to the rubber sheet coincides with the natural frequency of the same. In this case, the rubber sheet resonates and the vibration is amplified.
It is therefore an object of the present invention to provide an electric-component-mounter supporting apparatus"" which reduces the vibration of a floor resulting from the vibration of an electric-component mounter.
The present invention provides an electric-component-mounter supporting apparatus which has one or more of the technical features that are described below in respective paragraphs given parenthesized sequential numbers (1) to (15). Any technical feature which includes another technical feature shall do so by referring, at the beginning, to the parenthesized sequential number given to that feature. Thus, two or more of the following technical features may be combined, if appropriate. Each technical feature may be accompanied by a supplemental explanation, as needed. However, the following technical features and the appropriate combinations thereof are just examples to which the scope of the present invention is by no means limited.
(1) According to a first feature of the present invention, there is provided an apparatus for supporting an electric-component mounter including a substrate supporting device which supports a circuit substrate, an electric-component supplying device which supplies a plurality of electric components to be mounted on the circuit substrate, a mounting device which receives the electric components from the electric-component supplying device and mounts the electric components on the circuit substrate supported by the substrate supporting device, and a base member which supports the substrate supporting device, the electric-component supplying device, and the mounting device, the apparatus comprising at least one elastic member which is provided between the base member and a surface of a floor which supports the base member; and at least one damper which damps vibration of the base member and the floor surface relative to each other, the vibration resulting from elastic deformation of the elastic member. The mounting device may be; one which includes a plurality of electric-component (xe2x80x9cECxe2x80x9d) holders which are revolveable around a common axis; and an EC-holder positioning device which sequentially positions the EC holders at at least one predetermined operation position on the locus of revolution of the EC holders. The at least one operation position may include an EC-receive position where the mounting device receives the ECs from the EC supplying device. The EC-holder positioning device may be one which includes a plurality of rotary members which are rotatable about the above-indicated axis line, independent of each other, and which support the plurality of EC holders, respectively, at respective equal radial distances from the common axis; and a rotary-motion applying device which applies a rotary motion to each of the rotary members such that each of the rotary members is fully rotated by 360 degrees about the common axis while being stopped at least one time during its full rotation and having a predetermined time difference from each of its preceding and following rotary members. Otherwise, the EC-holder positioning device may be one which includes an intermittent-rotation body which is intermittently rotatable about the above-indicated common axis and which supports the plurality of EC holders at respective equal radial distances from the common axis; and a rotating device which intermittently rotates the intermittent-rotation body at the same angular pitch as that at which the EC holders are equiangularly spaced from each other about the common axis. The intermittent-rotation body which is rotated while supporting the EC holders may be replaced with a rotatable body which is rotatable by any desired angle in each of opposite directions. The mounting device may be one which includes at least one EC holder; and a movable member which supports the at least one EC holder and which is linearly movable in at least one of two directions perpendicular to each other on a plane. The mounting device may be one which is disclosed in U.S. patent application Ser. No. 08/977,662 assigned to the Assignee of the present application, i.e. one which includes a plurality of EC holders; the above-indicated, second EC-holder positioning device; and a movable member which supports the EC holders and the EC-holder positioning device and which is linearly movable in at least one of two directions perpendicular to each other on a plane. The substrate supporting device may be selected from various sorts of devices such as a device which supports and moves the circuit substrate, or a device which positions and supports the circuit substrate but does not move the same. The EC supplying device may be selected from various sorts of devices such as a movable device which stores the ECs and is movable, or a stationary device which stores the ECs but is not movable. Even if the EC mounter may vibrate when mounting the ECs on the circuit substrate, the elastic deformation of the elastic member permits the base member to move relative to the floor surface, so that the vibration of the EC mounter is prevented from being transmitted to the floor. In addition, the damper damps the relative vibration of the base member and the floor. Since the damper is provided between the base member and the floor, a portion of the vibration of the base member is damped by the damper whereas another portion of the vibration is transmitted to the floor via the damper. However, this portion is much smaller than the vibration which is transmitted to the floor in the case where neither the elastic member nor the damper is provided. Thus, the vibration of the floor is largely reduced, and the vibration of the base member is prevented from lasting for a long time, or being amplified because of resonance. The present apparatus can largely reduce the vibrational energy transmitted to the floor, than a conventional arrangement wherein a rubber sheet is inserted between a levelling sheet and a floor. That is, the present apparatus prevents the vibration of the floor, thereby preventing the vibration of other devices provided on the floor surface, the generation of noise, and the deterioration of life expectancy of the building in which the EC mounter is disposed. In addition, the present supporting apparatus damps the vibration of the base member, thereby reducing the amplitude of the vibration of the EC mounter. Therefore, for example, the substrate supporting device can reliably receive and pass the circuit substrate from and to the other devices, because the substrate supporting device is not so largely dislocated relative to the other devices. The elastic member may be provided by a coil spring that is elastically deformable in a direction parallel to its center axis line and directions perpendicular to the center axis line. In the case where the coil spring is disposed such that the center axis line of the coil spring extends perpendicularly to the floor surface, the coil spring can permit the relative vibration of the base member and the floor in all directions.
(2) According to a second feature of the present invention that includes the first feature (1), the mounter supporting apparatus further comprises at least one upper member which is fixed to the base member; and at least one lower member which is provided on the floor surface, the elastic member and the damper being provided between the upper and lower members. The elastic member may be provided between a first pair of upper and lower members, and the damper may be provided between a different, second pair of upper and lower members. According to the second feature, however, the elastic member and the damper are provided between the common pair of upper and lower members, so that the elastic member and the damper are connected to each other. Consequently the elastic deformation of the elastic member is effectively reduced by the damper, so that the relative vibration of the base member and the floor is effectively damped. In addition, according to this feature, the supporting apparatus including the elastic member and the damper can be produced and handled as a unit, which facilitates disposing the EC mounter on the floor. Though the upper member needs to be substantially fixed to the base member such that the upper member is not movable relative to the same, it need not be fixed using a fixing member or device such as bolts.
(3) According to a third feature of the present invention that includes the first or second feature (1) or (2), the mounting device receives, at a predetermined component-receive position, the electric components from the electric-component supplying device, and the electric-component supplying device comprises a movable electric-component supplying device which includes a movable table which is movable along a straight line passing through the component-receive position; and a plurality of component supplying units which are provided on the movable table and each of which is selectively positioned at the component-receive position by the movement of the movable table, and the damper damps the relative vibration of the base member and the floor surface in at least a direction parallel to the straight line. Each of the component supplying units may be one which includes an EC-supply portion and a tape feeding device which feeds an EC carrier tape including an EC accommodating tape accommodating the ECs, such that the ECs are fed one by one to the EC-supply portion; or otherwise one which includes an EC-supply portion and utilizes vibration, inclination, air flow, one or more conveyor belts, or the combination of two or more of them, for feeding the ECs in an array, such that the ECs are fed one by one to the EC-supply portion. In either case, each component supplying unit may further include an EC storing device which stores the ECs or the EC carrier tape; and a main frame. The main frame may, nor may not, support both the EC feeding device and the EC storing device. In the case where the main frame supports both the EC feeding device and the EC storing device, the main frame is attached to the movable table, whereby both the EC feeding device and the EC storing device are moved with the movable table. In the case where the main frame supports the EC feeding device but does not support the EC storing device, the main frame is attached to the movable table, whereby only the EC feeding device is moved with the movable table. In the latter case, the respective EC storing devices of the component supplying units may be provided on another movable table, or may be provided on a stationary table, i.e., may be fixed in position. Since the movable table on which the plurality of component supplying units are provided has a great mass, the base member is subjected, when the movement of the table is started or ended, to a great vibrational force in a direction parallel to the direction of movement of the table, so that the base member is vibrated in that direction. According to this feature, the damper effectively damps the vibration of the base member produced in the very direction. The linearly movable table may be replaced with a table which is movable along a line other than the straight line, for example, a circle, a circular arc (i.e. a part circle), a curve other than the circular arc, or a single line obtained by combining two or more of them. In the case of the circle, the linearly movable table may be replaced with a circular (i.e., full-circular) table which is rotatable about an axis line. In the case of the circular arc, the linearly movable table may be replaced with a sectorial table which is rotatable about an axis line. Each of the circular and sectorial tables can be said as a rotary table which is rotatable about an axis line. Also in the case where the linearly movable table is replaced with the rotary table, the elastic deformation of the elastic member permits the relative vibration of the base member and the floor and the damper damps the relative vibration. However, generally, the vibration of the base member produced in the case where the linearly movable table is started and stopped is much greater than that produced in the case where the rotary table is started and stopped. Thus, the present supporting apparatus is more advantageous when used with the linearly movable table than when used with the rotary table.
(4) According to a fourth feature of the present invention that includes the third feature (3), the damper damps the relative vibration of the base member and the floor surface in all directions on at least a vertical plane parallel to the straight line. As described above, when the linearly movable table is started and stopped, the base member is subjected to a great vibrational force in a direction parallel to the direction of movement of the table. Generally, the level or height position at which the vibrational force is applied to the base member is different from that at which the base member is supported by the mounter supporting apparatus. Therefore, the base member is subjected to a moment and accordingly a rotational vibration. Consequently a portion of the base member that is supported by the supporting apparatus is subjected to the vibration including all components corresponding to all directions on a vertical plane parallel to the direction of movement of the table. According to this feature, the damper damps the vibration produced in all the directions on the vertical plane. Thus, the present supporting apparatus effectively damps the vibration of the base member. In the case where the damper can additionally damp the vibration produced in a direction perpendicular to the direction of movement of the table on a plane parallel to the floor surface, the present apparatus can more effectively reduce the vibration of the base member.
(5) According to a fifth feature of the present invention that includes any one of the first to fourth features (1) to (4), the damper comprises an adjustable damper which has an adjustable vibration damping characteristic. The amplitude of the vibration of the floor resulting from the vibration transmitted thereto from the base member, changes depending upon the conditions of the floor, such as its rigidity, mass, and vibration damping characteristic. According to the fifth feature, the mounter supporting apparatus includes the adjustable damper whose vibration damping characteristic is adjustable. For example, when the EC mounter is disposed on the floor, the vibration damping characteristic of the damper is adjustable depending upon the conditions of the floor, so that the amplitude of vibration of the floor is minimized. The amplitude and frequency of the vibration transmitted from the base member to the floor change depending upon the conditions of the EC mounter, such as its mass and the speed of movement of its movable member or members. The mass of the movable EC supplying device as a whole changes as the number of the component supplying units mounted on the movable table changes, or as the number of the ECs stored in each of the supplying units changes. Also, the speed of operation of the EC mounter changes. However, the vibration damping characteristic of the damper can be adjusted depending upon those changes, so that the amplitude of vibration of the floor is not increased.
(6) According to a sixth feature of the present invention that includes the fifth feature (5), the adjustable damper comprises a movable member which is movable as a unit with the base member; a stationary member which is substantially immovable relative to the floor surface; a friction member which is held by one of the movable and stationary members such that the friction member is movable toward, and away from, the other of the movable and stationary members and is frictionally contactable with the other of the movable and stationary members; and a pressing device which is provided between the friction member and the one of the movable and stationary members and which presses, with an adjustable pressing force, the friction member against the other of the movable and stationary members. Since the friction member is pressed against the other of the movable and stationary members, friction occurs between the friction member and the other member, so that the vibrational energy is transformed into thermal energy. Consequently the vibration is damped. The vibration damping characteristic of the damper can be adjusted by adjusting the pressing force of the pressing device applied to the friction member.
(7) According to a seventh feature of the present invention that includes the sixth feature (6), the pressing device comprises a fluid-pressure-operated cylinder device which includes a cylinder and a piston and which is fixed to the one of the movable and stationary members, the piston pressing the friction member against the other of the movable and stationary members. The fluid-pressure-operated cylinder device may be an air- or liquid-pressure-operated cylinder device. In either case, the pressing force can be adjusted by adjusting the pressure of the fluid. The friction member may be fixed to the piston, or may be supported by the one of the movable and stationary members such that the friction member is movable in a direction parallel to the direction of movement of the piston.
(8) According to an eighth feature of the present invention that includes any one of the first to seventh features (1) to (7), the damper comprises an unadjustable damper which has an unadjustable vibration damping characteristic. Even the unadjustable damper whose vibration damping characteristic is not adjustable can damp the relative vibration of the base member and the floor, thereby preventing the amplification of the vibration of the EC mounter and the resonance of the same. In a particular case where it is not needed to adjust all the vibration damping capability of the present mounter supporting apparatus, it is possible to employ both the adjustable damper or dampers and the unadjustable damper or dampers, which contributes to reducing the production cost of the present apparatus.
(9) According to a ninth feature of the present invention that includes any one of the first to eighth features (1) to (8), the mounter supporting apparatus further comprises at least one inclination adjusting device which is provided between the base member and the floor surface and which adjusts an inclination of the base member relative to the floor surface. Since the EC mounter is supported on the floor via the elastic member such that the base member and the floor can be vibrated relative to each other, the base member is easily inclined relative to the floor surface. For example, it is difficult to produce a plurality of elastic members which can support, in the state of being elastically deformed, the base member such that the base member is not inclined relative to the floor surface. Thus, the base member is easily inclined because of the production-related errors of the elastic members. In addition, the weight of the EC supplying device as a whole changes as the number of the component supplying units employed changes or as the number of ECs stored in each of the component supplying units changes. This change also causes the inclination of the base member. The inclination adjusting device easily adjusts the inclination of the base member and keeps the base member parallel to the floor surface. Thus, the EC mounter does not fail to receive or pass the circuit substrate from or to its peripheral devices.
(10) According to a tenth feature of the present invention that includes the ninth feature (9), the inclination adjusting device comprises a gas spring which comprises a gas chamber and a compressible gas enclosed in the gas chamber; and a leveling valve device which adjusts a pressure of the compressible gas enclosed in the gas chamber of the gas spring and thereby adjusts the inclination of the base member relative to the floor surface. The gas may be air or nitrogen gas. The leveling valve device may be one which adjusts the gas pressure of the gas spring so as to keep a predetermined height of the gas spring.
(11) According to an eleventh feature of the present invention that includes the tenth feature (10), the leveling valve device comprises a mechanical valve device which is provided between the base member and the floor surface and which adjusts the inclination of the base member relative to the floor surface, based on movement of the base member and the floor surface relative to each other in a direction intersecting a horizontal plane. The leveling valve device may include a solenoid-operated switch valve device. However, this switch valve device is selectively switched between its gas-supply position where the valve permits a pressurized gas to be supplied from a gas source to the gas spring and its gas-relieve position where the valve device permits the gas to be relieved from the gas spring into the atmosphere. Thus, the solenoid-operated switch valve device cannot finely control or change the gas pressure of the gas spring. In contrast, the mechanical valve device can be gradually switched between its gas-supply position and its gas-relieve position, and can finely change the gas pressure of the gas spring. Thus, the mechanical valve device can accurately adjust the inclination of the base member.
(12) According to a twelfth feature of the present invention that includes any one of the first to eleventh features (1) to (11), the mounter supporting apparatus comprises a plurality of the elastic members each of which is provided between the base member and the floor surface; a plurality of the dampers each of which damps the vibration of the base member and the floor surface relative to each other; a plurality of upper members each of which is fixed to the base member; and a plurality of lower members each of which is provided on the floor surface, at least one first elastic member of the plurality of elastic members and at least one first damper of the plurality of dampers being provided between at least one first upper member of the plurality of upper members and at least one first lower member of the plurality of lower members, so as to provide a first supporting unit, at least one second elastic member of the plurality of elastic members and at least one second damper of the plurality of dampers being provided between at least one second upper member of the plurality of upper members and at least one second lower member of the plurality of lower members, so as to provide a second supporting unit, the first and second supporting units cooperating with each other to support the base member, at respective locations which are distant from each other in a horizontal direction. The horizontal direction is not limited to a specific direction. The two supporting units can stably support the base member relative to the floor surface. The respective dampers of the two supporting units may be either adjustable ones or unadjustable ones.
(13) According to a thirteenth feature of the present invention that includes the twelfth feature (12), the at least one first upper member comprises an elongate first upper member, the at least one first lower member comprises an elongate first lower member, the at least one second upper member comprises an elongate second upper member, and the at least one second lower member comprises an elongate second lower member, and the first supporting unit comprises two first elastic members one of which is provided at one of lengthwise opposite end portions of the elongate first upper member and one of lengthwise opposite end portions of the elongate first lower member and the other of which is provided at the respective other end portions of the elongate first upper and lower members, and two first dampers one of which is provided at the respective one end portions of the elongate first upper and lower members, and the other of which is provided at the respective other end portions of the elongate first upper and lower members, and the second supporting unit comprises two second elastic members one of which is provided at one of lengthwise opposite end portions of the elongate second upper member and one of lengthwise opposite end portions of the elongate second lower member and the other of which is provided at the respective other end portions of the elongate second upper and lower members, and two second dampers one of which is provided at the respective one end portions of the elongate second upper and lower members and, the other of which is provided at the respective other end portions of the elongate second upper and lower members. According to this feature, at least four elastic members and at least four dampers are provided at respective locations corresponding to the four corners of the base member. Thus, the supporting units can more stably support the base member relative to the floor surface, while permitting the base member to move relative to the floor surface.
(14) According to a fourteenth feature of the present invention that includes the twelfth or thirteenth feature (12) or (13), the electric-component supplying device comprises a component-supply table and a plurality of component supplying units which are provided on the component-supply table such that respective component-supply portions of the component supplying units are arranged along a straight line, and the mounter supporting apparatus further comprises an inclination adjusting device which is provided between the floor surface and a portion of the base member that supports the component-supply table, and which adjusts an inclination of the base member relative to the floor surface. The number of the component supplying units provided on the component-supply table may be changed depending upon, e.g., the sort of the circuit substrate used, and the number of ECs stored in each of the component supplying units decreases as the ECs are mounted one by one on the substrate. Thus, the weight of the EC supplying device changes. Therefore, the base member is inclined relative to the floor surface in a direction perpendicular to the direction in which the respective component-supply portions of the component supplying units are arranged. However, the inclination adjusting device can keep the base member substantially parallel to the floor surface.
(15) According to a fifteenth feature of the present invention that includes the fourteenth feature (14), the mounting device receives, at a predetermined component-receive position, the electric components from the electric-component supplying device, the straight line along which the respective component-supply portions of the component supplying units are arranged passes through the component-receive position, and the electric-component supplying device comprises a movable electric-component supplying device which comprises the component-supply table comprising a movable table which is movable along the straight line, and the component supplying units having the respective component-supply portions each of which is selectively positioned at the component-receive position by the movement of the movable table, and the first and second supporting units are provided at the respective locations which are distant from each other in the horizontal direction parallel to the straight line, and each of the first and second dampers of the first and second supporting units has a function of damping the relative vibration of the base member and the floor surface in all directions on at least a vertical plane parallel to the straight line. Since the movable table has a great mass, the base member is subjected to a great vibrational force in a direction parallel to the straight line passing through the component-receive position. However, according to this feature, the two supporting units are provided at the respective locations distant from each other in that direction. In addition, the dampers damp the relative vibration of the base member and the floor surface in all directions on the vertical plane parallel to the direction of movement of the table. Thus, the vibration which is transmitted to the floor is reduced, and the vibration of the EC mounter is reduced. Irrespective of where the movable table is started or stopped within its movement area or irrespective of whether the table is moved forward or backward along the straight line, the two supporting units permit the relative vibration of the base member and the floor surface, while damping the same. As the movable table is moved, the balance of respective loads applied to respective portions of the base member that are distant from each other in the direction of movement of the table changes, so that the base member is inclined. Therefore, it is preferred that one or more inclination adjusting devices be provided for adjusting the inclination of the base member in that direction. For example, two inclination adjusting devices each of which adjusts the distance between the base member and the floor surface are provided at respective locations which are distant from each other in the direction of movement of the table. Each of the two inclination adjusting devices may include the above-described combination of the gas spring and the leveling valve device.